9Departments of Surgery and Education and Public Health, University of Toronto, Toronto, Ontario, Canada

10Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada

11Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada

12Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada

13University Health Network, Toronto, Ontario, Canada

Correspondence to Dr M Anne Harris, School of Occupational and Public Health, Ryerson University, Toronto, ON M5B 2K3, Canada; anne.harris{at}ryerson.ca

Received 17 July 2012

Revised 4 December 2012

Accepted 14 December 2012

Published Online First 14 February 2013

Abstract

Background This study examined the impact of transportation infrastructure at intersection and non-intersection locations on bicycling
injury risk.

Methods In Vancouver and Toronto, we studied adult cyclists who were injured and treated at a hospital emergency department. A case–crossover
design compared the infrastructure of injury and control sites within each injured bicyclist's route. Intersection injury
sites (N=210) were compared to randomly selected intersection control sites (N=272). Non-intersection injury sites (N=478)
were compared to randomly selected non-intersection control sites (N=801).

Results At intersections, the types of routes meeting and the intersection design influenced safety. Intersections of two local streets
(no demarcated traffic lanes) had approximately one-fifth the risk (adjusted OR 0.19, 95% CI 0.05 to 0.66) of intersections
of two major streets (more than two traffic lanes). Motor vehicle speeds less than 30 km/h also reduced risk (adjusted OR
0.52, 95% CI 0.29 to 0.92). Traffic circles (small roundabouts) on local streets increased the risk of these otherwise safe
intersections (adjusted OR 7.98, 95% CI 1.79 to 35.6). At non-intersection locations, very low risks were found for cycle
tracks (bike lanes physically separated from motor vehicle traffic; adjusted OR 0.05, 95% CI 0.01 to 0.59) and local streets
with diverters that reduce motor vehicle traffic (adjusted OR 0.04, 95% CI 0.003 to 0.60). Downhill grades increased risks
at both intersections and non-intersections.

Conclusions These results provide guidance for transportation planners and engineers: at local street intersections, traditional stops
are safer than traffic circles, and at non-intersections, cycle tracks alongside major streets and traffic diversion from
local streets are safer than no bicycle infrastructure.

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